Muffler for removing particulate lead from exhaust gases of internal combustion engines

ABSTRACT

MUFFLER FOR AN INTERNAL COMBUSTION ENGINE WHICH IS ADAPTED FOR REMOVING PARTICULATE LEAD MATTER FROM THE EXHAUST GASES OF THE ENGINE TO PREVENT DISCHARGE OF THE NOXIOUS MATTER INTO THE SURROUNDING ATMOSPHERE. BASICALLY, THE MUFFLER COMPRISES A CANISTER OF THE USUAL TYPE EMPLOYED WITH INTERNAL COMBUSTION ENGINES, WHICH HAS AN INLET PORT FOR RECEIVING EXHAUST GASES FROM THE ENGINE AND AN OUTLET PORT FOR DISCHARGING THE EXHAUST GASES TO THE ATMOSPHERE. AN UPWARDLY SLOPING BOTTOM WALL OF THE CANISTER DEFINES A SUMP PORTION ADAPTED TO CONTAIN A FLUX COMPOSITION WHICH IS LIQUID AT THE USUAL TEMPERATURE RANGE OF THE EXHAUST GAS STREAM IN THE CANISTER. A WEIR MEMBER AND ONE OR MORE BAFFLE MEMBERS DEFINE COMPARTMENTS WITHIN THE CANISTER. FLOW OF THE EXHAUST GAS STREAM THROUGH THE CANISTER PROVIDES A DRIVING FORCE WHICH CONTINUOUSLY SPLASHES THE LIQUID FLUX AGAINST THE BAFFLE MEMBER SURFACES AND COMPARTMENT WALLS, THEREBY COATING THESE SURFACES WITH A FLUX FILM MEDIA WHICH ENTRAPS THE LEAD PARTICULATE MATTER IN THE GASES. A SLOTTED EDGE ON THE WEIR MEMBER METERS FLOW OF THE GAS-LIQUID BODY INTO ADJACENT COMPARTMENTS OF THE CANISTER. OPENINGS IN EACH BAFFLE MEMBER, WHICH ARE POSITIONED IN STAGGERED RELATION TO EACH OTHER, PROVIDE A TORTOUS FLOW PATH FOR THE EXHAUST GASES. SMALLER OPENINGS IN THE BAFFLE MEMBERS, TOGETHER WITH AN UPWARDLY SLOPING BOTTOM WALL ON THE CANISTER PERMIT CONTINUOUS FLOWBACK OF THE LIQUID FLUX TOWARD THE FORWARD PORTION OF THE CANISTER. ADDITIONAL FEATURES OF THE MUFFLER INCLUDE (1) A GAS FLOW PORT IN THE WEIR MEMBER, WHICH IS OPENED OR CLOSED BY PRESSURE OF THE EXHAUST GASES, TO PROVIDE FOR GAS FLOW THROUGH THE CANISTER IN THE EVENT OF SOLIDIFICATION OF THE FLUX COMPOSITION; AND (2) FILLING THE REARMOST CHAMBER OF THE CANISTER WITH A POROUS MATERIAL CAPABLE OF TRAPPING AND SEPARATING THE LIQUID FLUX FROM THE EXHAUST GASES.

Feb. 16, 1971 F. J. LOWES 3,563,029

MUFFLER FOR REMOVING PARTICULATE LEAD FROM EXHAUST GASES OF INTERNALCOMBUSTION ENGINES Filed March 13, 1969 INVENTOR. Frea er/ck J. L 0 W953,563,029 MUFFLER FOR REMOVING PARTICULATE LEAD FROM EXHAUST GASES OFINTERNAL COM- BUSTION ENGINES Frederick J. Lowes, Midland, Mich.,assignor to The Dow Chemical Company, Midland, Mich., a corporation ofDelaware Filed Mar. 13, 1969, Ser. No. 806,809

Int. Cl. F01n 3/04 U.S. Cl. 60-30 8 Claims ABSTRACT OF THE DISCLOSUREMufller for an internal combustion engine which is adapted for removingparticulate lead matter from the exhaust gases of the engine to preventdischarge of the noxious matter into the surrounding atmosphere.Basically, the muffler comprises a canister of the usual type employedwith internal combustion engines, which has an inlet port for receivingexhaust gases from the engine and an outlet port for discharging theexhaust gases to the atmosphere. An upwardly sloping bottom wall of thecanister defines a sump portion adapted to contain a flux compositionwhich is liquid at the usual temperature range of the exhaust gas streamin the canister. A weir member and one or more bafile members definecompartments within the canister.

Flow of the exhaust gas stream through the canister provides a drivingforce which continuously splashes the liquid flux against the battlemember surfaces and compartment walls, thereby coating these surfaceswith a flux film media which entraps the lead particulate matter in thegases. A slotted edge on the weir member meters flow of the gas-liquidbody into adjacent compartments of the canister. Openings in each bafliemember, which are positioned in staggered relation to each other,provide a tortuous flow path for the exhaust gases. Smaller openings inthe baflle members, together with an upwardly sloping bottom wall on thecanister permit continuous flowback of the liquid flux toward theforward portion of the canister. Additional features of the mufllerinclude (1) a gas flow port in the weir member, which is opened orclosed by pressure of the exhaust gases, to provide for gas flow throughthe canister in the event of solidification of the flux composition; and(2) filling the rearmost chamber of the canister with a porous materialcapable of trapping and separating the liquid flux from the exhaustgases.

BACKGROUND OF THE INVENTION The invention relates to a mufller for aninternal combustion engine. More specifically, the invention concerns amuffler adapted to remove particulate lead from the engine exhaustgases, but which also performs the usual function of a mufller as asound damping device.

Gasolines employed as fuels for the internal combustion engines ofautomobiles, buses, trucks, and the like, usually contain an additivematerial which improves the octane rating and gives an anti-knockcharacteristic to the fuel. The conventional anti-knock additivesusually employed in automotive gasolines are tetraalkyl lead compounds,such as tetraethyl lead, tetramethyl lead and mixtures thereof. Toprevent lead deposits in the combustion chamber of the engine, however,the leaded fuels usually also contain a scavenger compound such as amixture of ethylene dichloride-ethylene dibromide. During combustion thescavenger compounds remove the lead components in the form ofparticulate lead compounds which are carried out of the engine with theexhaust gases.

" United States Patent O Since the conventional automotive mufllers haveno means of removing the particulate lead matter, a substantial quantityof this undesirable material is discharged into the atmosphere each day,where it adds to the general air pollution problem and, because of itsknown toxicity, represents a recognizable health hazard.

OBJECTS OF THE INVENTION A broad object of the invention is to provide amuffler suitable for performing the usual function of damping enginenoise, as well as being adapted to remove particulate lead matter fromthe exhaust gases.

A more specific object is a mufiler containing a flux composition whichis a liquid at the temperature of exhaust gases flowing through themufller, whereby coaction of the exhaust gases with the liquid fluxcontinuously wets inner compartment wall and bafile surfaces of themufller to provide a media for entrapping particulate lead matter in theexhaust gases.

SUMMARY OF THE INVENTION Broadly stated, the invention provides amufller for an internal combustion engine, the muffler being adapted toremove lead particulate matter from the exhaust gases of the engine.Basically, the mufller comprises a canister having roll members definingan enclosed vessel with an inlet port for directing an exhaust gasstream into the canister and an outlet port for discharging the exhaustgas stream. The bottom wall of the canister is sloped to provide a sumpportion adapted to contain a flux composition which is liquid at theusual temperature range of the exhaust gas stream.

A weir means positioned in the canister at a point downstream from theinlet port is adapted to deflect the exhaust gas stream against theliquid flux contained in the sump portion. The weir means additionallyincludes a means for regulating displacement of the liquid compositionby the exhaust gases from the sump portion. The canister also includes abaflle means positioned within the canister at a point downstream fromthe weir means, the baffle means being adapted to permit passage of theexhaust gas stream therethrough, the deflection of the gas stream by thebafile creating a tortuous path for the gas through the baffle. Asubstantial amount of the liquid flux displaced from the sump portion bythe exhaust gas stream is continuously directed onto the surface of thebaffle and the walls of the canister. Coating of the bafile and wallsurfaces with the liquid flux provides a film media which entraps leadparticulate matter in the gas stream.

Flux compositions contemplated as suitable lead-trapping media in themufller of this invention are preferably various inorganic acids, basesand salts which (I) exist as, or are capable of, forming liquidcompositions at the usual temperature range of exhaust gases flowingthrough a mufller, and (2) which will remain stable under suchtemperature conditions. The usual temperature range of exhaust gases ina conventional automobile engine mufller are from about 500 F. to 1500F., depending on how close the muffler is located to the exhaustmanifold. As regards stability, the flux compositions should be thosematerials which are not subject to irreversible change with the emissionof objectionable vapors. For example, o-phosphoric acid, which is one ofthe flux compositions useful in the practice of this invention, canconvert to polyor pyrophosphoric acid when heated sufliciently toeliminate water in the compound, but will readily revert back to theortho form when cooled in a humid environment. As a furtherillustration, carbonates may derive from hydroxides at the loweroperating temperatures in a mufller, but the carbonates will form oxidesat higher temperatures.

Certain metallurgical fluxes, known commercially as Holden Osquenchfluxes, which comprise primarily various mixtures of sodium hydroxideand potassium hydroxide, are particularly preferred in the practice ofthis invention. These flux compositions are solid materials at roomtemperature, but readily form liquid compositions on contact with thehigh temperature exhaust gases in the mufller. Other alkali metalcompositions contemplated as suitable fluxes in this invenion includevarious alkali metal salts, such as sodium acetate, potassium acetate,and mixtures thereof. With regard to acid compositions, commerciallyavailable aqueous solutions of orthophosphoric acid have beensuccessfully employed as flux compositions in the mutfier of thisinvention. Other oxygen acids of phosphorous and acid salts thereof,which are proposed as suitable flux compositions, include hypophosphoricacids, pyrophosphoric acid, sodium dihydrogen phosphate, disodiumhydrogen phosphate, trisodiurn phosphate and the like.

Materials used to fabricate the canister and the configuration of thedevice itself are not considered critical. Metals having high corrosionresistance are preferred for obvious reasons. Suitable materials includecertain cladded metals such as iron-stainless steel, iron-aluminum,iron-titanium, and the like. For ease of fabrication the preferred shapeof the canister is either the usual cylindrical or elliptical shape ofthe conventional automotive mufflers or the substantially rectangularshape of the muffler illustrated herein. Other factors which shoulddetermine the preferred shape of the canister include (1) the ability ofthe device to remove lead from exhaust gases and (2) the capability ofthe muffler to function as a sound damper for engine noise.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a side elevation view, partlyin section, of a rnuflller according to a preferred embodiment of theinvention.

FIG. 2 is a cross-sectional view, taken along line 22 of FIG. 1, whichillustrates a weir member as positioned in the muffler.

FIG. 3 is a cross-sectional view, taken along line 3-3 of FIG. 1, whichillustrates a baflle member, as positioned in the muffler.

FIG. 4 is a cross-sectional view, taken along line 4-4 of FIG. 1, whichillustrates a second batflle member, as positioned in the mufiler.

The drawing illustrates only one of numerous embodiments within thescope of the invention and the form shown is selected for convenientillustration and clear demonstration of the principles involved.

DESCRIPTION OF A PREFERRED EMBODIMENT Referring to the drawing, withparticular reference to FIG. 1, there is illustrated a muffler similarin construc tion to the usual type employed as a sound damper on aninternal combustion engine. The mufiler comprises basically a canister10, providing a generally enclosed vessel, as defined by an upstandingfront wall 12 and an up standing rear wall 14, which are connected by agenerally horizontally-disposed top wall 16, and a bottom 'wall 18, thebottom wall sloping generally upwardly from the front wall to the rearwall of the canister. Additionally, a pair of upstanding sidewalls 19and 20, as best shown in FIG. 2, join the front and rear walls .12 and14 with top and bottom walls 16 and 18, giving the canister a generallyrectangular configuration. The front wall 12 of canister 10 includes aninlet port 21, which is adapted for connection to the exhaust pipe of aconventional automobile engine to receive exhaust gases from the engine.The exhaust gases are discharged from the canister .10 through an outletport 22, which is located in the 4 rear wall 14 of the canister and isadapted for connection to the tail pipe of an automobile engine.

As illustrated in FIG. 1, the preferred embodiment of the canister 10 isdivided into a series of compartments. A first compartment 24 is definedby a weir member 26, which is generally vertically disposed in thecanister '10 and spaced from the front wall 12 thereof. A first bafflemember 28, which is generally vertically disposed in the canister andspaced behind the weir member 26, defines a second compartment 30. Asecond generally vertically disposed bafile member 32, which is spacedbehind the first baffie member 28, defines a third compartment 34. Afourth (or rear) compartment 36 is defined by the space between thebaffle member 32 and the rear wall 14 of canister 10.

The upwardly sloping bottom Wall 18 defines generally a sump portion(not numbered), which is subdivided into the compartments 24, 30, 34 and36. That portion of the sump as defined by the compartments 24, 30 and34 provides a container for a flux composition 38, the flux compositionbeing present in the canister 10 as a liquid at the temperature range ofthe exhaust gases flowing through the canister. As indicated by thearrows in FIG. 1, the exhaust gases flowing through the canister act asa driving force to continuously splash the liquid flux against the wallsof the compartments 30 and #34 and the surfaces of bafile members 28 and32. This splashing action coats the bafile and compartment Wall surfaceswith a flux film media which entraps particulate lead matter in theexhaust gases.

As best shown in FIG. 2, a plurality of generally V- shaped slots 40,which define the bottom edge of weir member 26, provide means fordistributing and regulating rearward flow of the exhaust gases anddisplacement of the liquid flux composition 38 within the canister 10.The exhaust gases are constrained to follow a tortuous path in theirflow through the canister 10, as provided by the series of openings 42in bafiie member 28, and similar opening 44 in bafiie member 32, theopenings being staggered relative to each other so that the gases cannotflow in a straight line. By providing a tortuous path for the exhaustgases, the particulate lead matter in the gases, which tends to travelin straight lines, is induced to strike the compartment walls and bafflesurfaces Where it clings to the flux film coating on these surfaces.

The sump portion provided by the sloping bottom wall 13, in conjunctionwith the smaller openings 46, positioned along the bottom edge of bafilemember 28, and the similar openings 48 in bafile member 32, permit thereturn (or forward) flow of the flux composition 38 in canister 10. Bythis means, therefore, the flux composition may be maintained at at alltimes at the desired operating level in the canister. During flow of theexhaust gases through canister 10, small amounts of the flux composition38 may be carried over into compartment 36 by the exhaust gases, andthereby be accidentally discharged from the canister through outlet port22. T o prevent such loss of the flux composition, the compartment 36may be filled with a porous material 50, such as steel wool, which willtrap and separate the liquid fiuX from the exhaust gases. The separatormaterial 50 is considered optional equipment, since it is not requiredfor normal operation of the canister 10.

In the event of solidification of the liquid flux composition 38, suchas during cold weather operation, a gas flow port in the weir member 26provides for uninterrupted flow of exhaust gases through the canister'10. The gas flow port is defined by an aperture 52 in weir member 26and a closure member 54 mounted on the rearward side of weir member 26in direct alignment with aperture 52. To provide for opening and closingof the aperature 52, the closure member 54 is biased against weir member26 by a spring hinge or other suitable biasing means. During normaloperation of the canister 10 the aperture 52 is closed, that is, theclosure member 54 remains biased against weir member 26. Should theliquid flux composition 38 solidify, however, the pressure of theincoming exhaust gases in canister 10 soon becomes high enough incompartment 24 to force closure member 54 open. This permits the exhaustgases to flow through the weir member 26, rather than under the weirmember in the intended manner. As soon as the heat from the exhaustgases flowing into compartment 24 is able to convert the solid fluxcomposition to a liquid, usually a very short time, the canister willresume its normal operation.

The canister 10 may be filled with flux composition 38 through a fillercap 56, which is mounted on the upper wall 16 to provide access to the(forward) compartment 24. Although separate filler caps for compartments30 and 34 may be provided when the flux composition 38 is a solidmaterial as initially charged to the canister 10, such additional fillercaps are not considered essential to the practice of the invention. Inother words, the compartment 24 may be charged with a sufiicient amountof solid flux composition to provide the desired liquid level incompartments 30 and 34 as the flux is liquefied by the exhaust gases.When it is desired to clean the canister 10 or to replace the fluxcomposition with a fresh solution, the canister may be drained through apetcock 58 mounted on the bottom wall 18 at the forward end ofcompartment 24.

OPERATION In a typical operation, the capability of the present mufflerto remove lead particulate matter from engine exhaust gases wasdemonstrated by employing the canister 10 in a series of test runs on aconventional multicylinder automobile engine. The tests were run on aFord V-8 engine, 289 cu. in., single exhaust. The fuel used was aconventional leaded gasoline of the type generally employed in researchstudies of internal combustion en- 1 the procedures described herein:

Example I In the first run the flux composition 38, as charged to thecanister '10, was a solid material comprising essentially a mixture ofsodium hydroxide and potassium hydroxide (hydrate), know commercially asHolden Osquench 330040. Analysis of the flux composition by knownprocedures revealed that it contained on lead components.

The engine was started and allowed to run at 2000 r.p.m. for about 30minutes under no-load (idling) conditions. During this time the exhaustgas pressure at the manifold was balanced against the pressure in thecanister and the exhaust gases were allowed to flow freely through thecanister. After the initial warm-up period the flux composition wasadded to the canister 10 and the engine was allowed to run for anadditional 30-minute period to stabilize the engine operatingconditions, such as the desired r.p.m., operating temperature andrebalance of the exhaust gas pressure. The engine was then runcontinuously for a period of about 9 hours, with exhaust gases flowingthrough the canister during the entire period. During the run the vacuumpressure was gradually decreased in increments of 2 in. Hg, from idle towide open throttle, while holding the engine at 2000 rpm. At the end ofthe 9-hour period the engine was shut off and the canister 10 allowed tocool to room temperature.

Five samples of the flux composition were obtained 6 at various placesin the canister 10, ranging from the forward portion to the rear portionthereof, with each sample being analyzed for lead content. Reading fromfront to rear of the canister, the lead content of the respectivesamples was as follows (computed as percent by weight of sample): Sample10.003%; Sample 20.l5%; Sample 30.09%; Sample 4-0.029% and Sample 5l.5%.

Example II In the second run the flux composition 38, as charged to thecanister 10, was a solid material comprising essentially a mixture ofsodium hydroxide and potassium hydroxide, with trace amounts ofpotassium chloride, known commercially as Holden Osquench 300.

The test procedure and engine operating conditions were essentiallythose described in Example I, with the engine being allowed to runcontinuously for a period of about 26 hours. After the canister 10 wasallowed to cool to room temperature, three (3) samples of the fluxcomposition were obtained at various points within the canister asfollows: Sample 1 was taken from the surface of the flux composition incompartment 24; Sample 2 was taken from the center of the fluxcomposition in compartment 30; and Sample 3 was taken from the forwardsurface of bafile member 32. Lead content analysis of each sample gavethe following result (computer as percent by weight of sample): Sample1-0.3%; Sample 20.01%; and Sample 3-0.6%.

Example III For the third test run the flux composition 38, as chargedto the canister 10, was a liquid composition comprising a commerciallyavailable aqueous solution of orthophosphoric acid.

The procedure and engine operating conditions were essentially those setout in Example I, with the engine being run continuously for a period ofabout 19 hours. After the canister .10 was allowed to cool, three (3)samples of the flux composition were obtained at the same positions inthe canister as the samples of Example II. Analysis of the respectivesamples for lead content gave the following results (computed as percentby weight of sample): Sample 10.l5%; Sample 20.l7%; and Sample 30.20%.

As the data of the foregoing examples clearly indicate, the mufller ofthis invention effectively removes a substantial quantity of the leadcomponent present in the exhaust gases of internal combustion engines.-In additional experiments conducted in the practice of this invention,it was found that (l) the sound damping characteristics of the presentmufiier are at least equivalent to conventional mutfier, and (2) theback pressure of the present muffler is significantly less than that ofthe conventional mufflers.

What is claimed is:

1. Method for removing lead particulate matter from the exhaust gases ofan internal combustion engine, which comprises:

providing in the exhaust system of the engine an enclosed canisterincluding an inlet port, a weir means positioned downstream from theinlet port and having thereon a liquid flow regulating means, at leastone baffle means having openings therein and positioned downstream fromthe weir means, a sump portion positioned below the weir means andcontaining a flux composition comprising an inorganic acid, base or saltwhich is a stable, liquid composition at a temperature of from about 500F. to 1500 F., and an outlet port positioned downstream from the bafliemeans;

directing the lead-containing exhaust gas stream through the inlet portinto the canister;

deflecting the gas stream against the weir means to direct it downwardlyagainst the liquid flux; displacing with the exhaust gas stream asubstantial amount of the liquid flux from the sump portion through theliquid flow regulating means of the weir means; continuously splashingthe displaced liquid flux against the bafi'le means with the exhaust gasstream to coat the bafile surface with a film of the liquid flux;

directing the exhaust gas stream through the openings in the bafilemeans, while impinging the particulate lead matter against the bafflesurface to entrap the particles in the fiux coating thereon;

discharging the exhaust gas stream from the canister through the outletport.

2. The method of claim 1 in which the flux composition is an alkalimetal base selected from the group consisting essentially of sodiumhydroxide, potassium hydroxide, and mixtures of sodium hydroxide andpotassium hydroxide.

3. The method of claim 1 in which the flux composition is an alkalimetal salt selected from the group consisting essentially of sodiumacetate, potassium acetate, and mixtures of sodium acetate and potassiumacetate.

4. The method of claim 1 in which the flux composition is an oxygen acidof phosphorous selected from the group consisting of orthophosphoricacid, hypophosphoric acid and pyrophosphoric acid.

5. The method of claim 1 in which the flux composition is an oxygen acidsalt of phosphorous selected from the group consisting of sodiumdihydrogen phosphate, disodium hydrogen phosphate and trisodiumphosphate.

6. In the exhaust system of an internal combustion engine, a muffler forremoving lead particulate matter from the exhaust gases of the engine,which comprises:

(I) a canister generally defining an enclosed vessel which has:

(A) an inlet port for directing an exhaust gas stream into the canister;

(B) an outlet port for discharging the exhaust gas stream from thecanister;

(C) a front wall;

(D) a rear wall;

(E) a top wall and side walls connecting the front and rear walls;

(F) a bottom wall connecting the front and rear walls and slopingupwardly from the front wall to the rear wall to define a sump portionin the canister;

(G) the said sump portion containing a flux composition which is astable, liquid composition at a temperature of from about 500 F. to 1500E;

(II) a weir means which:

(A) is substantially vertically disposed within the canister;

(B) is spaced from the front wall of the canister to define a firstcompartment in the sump portion;

(C) is adapted to deflect the gas stream downwardly against the fluxcomposition contained in the first compartment of the sump portion;

(D) has liquid flow regulating means thereon for 60 regulatingdisplacement of the fiux composition from said first compartment;

(E) has an aperture therein which is positioned above the liquid fiowregulating means and a clo- '8 sure member for the aperture which ismounted on the weir means in alignment with the aperture, the closuremember being biased against the weir means to permit opening of theaperture in response to pressure of the exhaust gas stream against theclosure member;

(III) a first baffle means which:

(A) is substantially vertically-disposed within the canister;

(B) is spaced from the weir means to define a second compartment in thesump portion of the canister;

(C) has gas-flow openings therein;

(D) has liquid flow openings therein, said openings being positioned inthe bafile below the gasflow openings;

(IV) a second bafile means which: 9

(A) is substantially vertically-disposed within the canister;

(B) is spaced from the first bafile means to define a third compartmentin the sump portion of the canister;

(C) is spaced from the rear wall of the canister to define a fourthcompartment in the sump portion of the canister;

(D) has gas-flow openings therein;

(E) has liquid-flow openings therein, said openings being positioned inthe bafl1e below the gas-flow openings;

(F) whereby deflection of the exhaust gas stream downwardly against theflux composition contained in the first compartment displaces a portionof the flux composition from the first compartment into the second andthird compartments, in which compartments the displaced fluxcontinuously splashes against the first and second bafile means to coatthe surfaces of said baffie means with a flux film which entraps leadparticulate matter impinging on said film.

7. The mufller of claim 6 wherein the liquid flow regulating means onthe weir means comprises a plurality of generally V-shaped slots whichdefine the bottom edge of the weir means.

8. The muffler of claim 6 wherein the fourth compartment of the canisterincludes means for separating the liquid flux composition from theexhaust gases.

References Cited UNITED STATES PATENTS DOUGLAS HART, Primary ExaminerUS. Cl. XR.

